Hi! I'm not sure what you can do to make sure they don't yellow but as far as the photo abum part goes... I was in ACMoore (don't know id they have that craft store where you are) recently and they had all kinds of super cheap photo albums and many shapes and sizes. You could buy one that you like the look of, maybe paint it or cover it in plain paper and then glue on the comic cut-outs.

Krylon makes a sealant that supposedly keeps documents from yellowing (or at least, so the back of the can says). I've never used it on actual paper before (I've only used it to seal completed plaster sculptures), but for the projects I have used it on, it's worked wonderfully and seems to be impermeable. You could also do what I did with the postcard notebooks and use spray mount to attach it behind tracing plastic found in craft store sewing sections. I posted under the playing card notebooks if you want to see pictures or read the rest of that post. Hope this helps!